An error log is a listing of the error messages and warnings that showed up for one reason or another while your visitors were looking through your website. This sort of a log includes raw info about the way the web server has addressed requests in different situations. An error message might appear if, for instance, a link leads to a site or a file that is not on the server, if the code on a certain page can't be processed, if someone is trying to access the Internet site or its back office via an IP address which is blocked by an .htaccess rule and so forth. The data in the error log includes the IP address of the website visitor, what error message came out and the root cause for the web server to show it, the entire path to the file which induced the error and the exact time of the event. Having this data will permit you to find out if any part of your Internet site has a problem, which you may then clear up. Therefore, your site visitors will have a better experience and you may optimize the website for best performance.